Aligning osgViewer Camera with an Image - openscenegraph

As a precursor to render to texture, I am trying to simply align the osgViewer's camera to a texture mapped plane.
This is the code I employ for the same:
int main()
{
osgViewer::Viewer viewer;
osg::ref_ptr<osg::Image> image = osgDB::readImageFile("path//to//file.png");
if (!image.valid())
{
assert(false);
return 1;
}
osg::ref_ptr<osg::Geometry> pictureQuad = osg::createTexturedQuadGeometry(osg::Vec3(0.f,0.f,0.f),
osg::Vec3(image->s(),0.f,0.f),
osg::Vec3(0.f,0.f,image->t()),
0.f,
0.f,
image->s(),
image->t());
osg::ref_ptr<osg::TextureRectangle> textureRect = new osg::TextureRectangle(image);
textureRect->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
textureRect->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
textureRect->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
textureRect->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
pictureQuad->getOrCreateStateSet()->setTextureAttributeAndModes(0, textureRect.get(),
osg::StateAttribute::ON);
pictureQuad->getOrCreateStateSet()->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON);
osg::ref_ptr<osg::Geode> geode = new osg::Geode();
geode->setDataVariance(osg::Object::DYNAMIC);
geode->addDrawable(pictureQuad.get());
osg::StateSet *state = geode->getOrCreateStateSet();
state->setMode( GL_LIGHTING, osg::StateAttribute::PROTECTED | osg::StateAttribute::OFF );
viewer.setSceneData(geode);
osg::ref_ptr<osg::Camera> camera = viewer.getCamera();
while( !viewer.done() )
{
camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
camera->setProjectionMatrix(osg::Matrix::ortho2D(0.f, image->s(), 0.f, image->t()));
camera->setViewMatrixAsLookAt(osg::Vec3f(0.f, -100.f, 0.f),
osg::Vec3f(image->s()*0.5, 0.f, image->t()*0.5f),
osg::Vec3f(0.f, 0.f, 1.f));
viewer.frame();
}
return 0;
}
However, the results show me a view that is completely skewed. Can someone please point out the bug in my code?

In
camera->setViewMatrixAsLookAt(osg::Vec3f(0.f, -100.f, 0.f), // eye
osg::Vec3f(image->s()*0.5, 0.f, image->t()*0.5f), // center
osg::Vec3f(0.f, 0.f, 1.f)); // up vector
Your eye is on the ground, looking at the center of your image, which is up from it, so you would naturally expect a slanted image.
Try putting the eye at height image->t()*0.5 so the view is straight-on.

Related

3d model not rendered (DirectX 12)

I am developing a small program that load 3d models using assimp, but it does not render the model. At first I thought that vertices and indices were not loaded correctly but this is not the case ( I printed on a txt file vertices and indices). I think that the probem might be with the position of the model and camera. The application does not return any error, it runs properly.
Vertex Struct:
struct Vertex {
XMFLOAT3 position;
XMFLOAT2 texture;
XMFLOAT3 normal;
};
Input layout:
D3D12_INPUT_ELEMENT_DESC inputLayout[] =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, D3D12_APPEND_ALIGNED_ELEMENT, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 }
};
Vertices, texcoords, normals and indices loader:
model = new ModelMesh();
std::vector<XMFLOAT3> positions;
std::vector<XMFLOAT3> normals;
std::vector<XMFLOAT2> texCoords;
std::vector<unsigned int> indices;
model->LoadMesh("beast.x", positions, normals,
texCoords, indices);
// Create vertex buffer
if (positions.size() == 0)
{
MessageBox(0, L"Vertices vector is empty.",
L"Error", MB_OK);
}
Vertex* vList = new Vertex[positions.size()];
for (size_t i = 0; i < positions.size(); i++)
{
Vertex vert;
XMFLOAT3 pos = positions[i];
vert.position = XMFLOAT3(pos.x, pos.y, pos.z);
XMFLOAT3 norm = normals[i];
vert.normal = XMFLOAT3(norm.x, norm.y, norm.z);
XMFLOAT2 tex = texCoords[i];
vert.texture = XMFLOAT2(tex.x, tex.y);
vList[i] = vert;
}
int vBufferSize = sizeof(vList);
Build of the camera and views:
XMMATRIX tmpMat = XMMatrixPerspectiveFovLH(45.0f*(3.14f/180.0f), (float)Width / (float)Height, 0.1f, 1000.0f);
XMStoreFloat4x4(&cameraProjMat, tmpMat);
// set starting camera state
cameraPosition = XMFLOAT4(0.0f, 2.0f, -4.0f, 0.0f);
cameraTarget = XMFLOAT4(0.0f, 0.0f, 0.0f, 0.0f);
cameraUp = XMFLOAT4(0.0f, 1.0f, 0.0f, 0.0f);
// build view matrix
XMVECTOR cPos = XMLoadFloat4(&cameraPosition);
XMVECTOR cTarg = XMLoadFloat4(&cameraTarget);
XMVECTOR cUp = XMLoadFloat4(&cameraUp);
tmpMat = XMMatrixLookAtLH(cPos, cTarg, cUp);
XMStoreFloat4x4(&cameraViewMat, tmpMat);
cube1Position = XMFLOAT4(0.0f, 0.0f, 0.0f, 0.0f);
XMVECTOR posVec = XMLoadFloat4(&cube1Position);
tmpMat = XMMatrixTranslationFromVector(posVec);
XMStoreFloat4x4(&cube1RotMat, XMMatrixIdentity());
XMStoreFloat4x4(&cube1WorldMat, tmpMat);
Update function :
XMStoreFloat4x4(&cube1WorldMat, worldMat);
XMMATRIX viewMat = XMLoadFloat4x4(&cameraViewMat); // load view matrix
XMMATRIX projMat = XMLoadFloat4x4(&cameraProjMat); // load projection matrix
XMMATRIX wvpMat = XMLoadFloat4x4(&cube1WorldMat) * viewMat * projMat; // create wvp matrix
XMMATRIX transposed = XMMatrixTranspose(wvpMat); // must transpose wvp matrix for the gpu
XMStoreFloat4x4(&cbPerObject.wvpMat, transposed); // store transposed wvp matrix in constant buffer
memcpy(cbvGPUAddress[frameIndex], &cbPerObject, sizeof(cbPerObject));
VERTEX SHADER:
struct VS_INPUT
{
float4 pos : POSITION;
float2 tex: TEXCOORD;
float3 normal : NORMAL;
};
struct VS_OUTPUT
{
float4 pos: SV_POSITION;
float2 tex: TEXCOORD;
float3 normal: NORMAL;
};
cbuffer ConstantBuffer : register(b0)
{
float4x4 wvpMat;
};
VS_OUTPUT main(VS_INPUT input)
{
VS_OUTPUT output;
output.pos = mul(input.pos, wvpMat);
return output;
}
Hope it is a long code to read but I don't understand what is going wrong with this code. Hope somebody can help me.
A few things to try/check:
Make your background clear color grey. That way, if you are drawing black triangles you will see them.
Turn backface culling off in the rendering state, in case your triangles are back to front.
Turn depth test off in the rendering state.
Turn off alpha blending.
You don't show your pixel shader, but try writing a constant color to see if your lighting calculation is broken.
Use NVIDIA's nSight tool, or the Visual Studio Graphics debugger to see what your graphics pipeline is doing.
Those are usually the things I try first...

Monogame pixel shader - Texture passing as completely transparent

I'm trying to make a distortion shader for water in my game. I have the screen's rendertarget, and the water mask rendertarget, and I'm try to simply capture the pixels underneath the mask, but I can't get it to work. When I pass the textures, it's as if they're both completely transparent. What could I be doing wrong?
Shader:
texture Screen;
texture Mask;
float2 Offset;
sampler ScreenSampler = sampler_state
{
Texture = <Screen>;
};
sampler MaskSampler = sampler_state
{
Texture = <Mask>;
};
float4 PixelShaderFunction(float2 texCoord: TEXCOORD0) : COLOR
{
float4 mask = tex2D(MaskSampler, texCoord);
float4 color = tex2D(ScreenSampler, texCoord + Offset);
if (mask.a > 0)
{
return color;
}
return mask;
}
technique Technique0
{
pass Pass0
{
PixelShader = compile ps_4_0 PixelShaderFunction();
}
}
Render target:
Doldrums.Game.Graphics.GraphicsDevice.SetRenderTarget(renderTargetDistortion);
Doldrums.Game.Graphics.GraphicsDevice.Clear(Color.Transparent);
waterEffect.Parameters["Screen"].SetValue(Doldrums.RenderTarget);
waterEffect.Parameters["Mask"].SetValue(renderTargetWater);
waterEffect.Parameters["Offset"].SetValue(Doldrums.Camera.ToScreen(renderTargetPosition));
sprites.Begin(SpriteSortMode.Deferred, null, null, null, null, waterEffect);
sprites.Draw(renderTargetWater, Vector2.Zero, Color.White);
sprites.End();
Finally, rendering the rendertarget:
sprites.Draw(renderTargetDistortion, renderTargetPosition, Color.White);
I had the exact same "issue"using monogame during my development. The problem here is easily fixed, change this:
sprites.Begin(**SpriteSortMode.Deferred**, null, null, null, null, waterEffect);
sprites.Draw(renderTargetWater, Vector2.Zero, Color.White);
sprites.End();
To another mode like this:
sprites.Begin(**SpriteSortMode.Immediate**, null, null, null, null, waterEffect);
sprites.Draw(renderTargetWater, Vector2.Zero, Color.White);
sprites.End();
Have fun :)

how to apply gradient effect on Image GDI

How can I apply gradient effect on image like this image in c#. I have a transparent image with black drawing I want to apply 2 color gradient on the image is this possible in gdi?
Here is the effect i want to achieve
http://postimg.org/image/ikz1ie7ip/
You create a PathGradientBrush and then you draw your texts with that brush.
To create a bitmap filled with a gradient brush you could do something like:
public Bitmap GradientImage(int width, int height, Color color1, Color color2, float angle)
{
var r = new Rectangle(0, 0, width, height);
var bmp = new Bitmap(width, height);
using (var brush = new LinearGradientBrush(r, color1, color2, angle, true))
using (var g = Graphics.FromImage(bmp))
g.FillRectangle(brush, r);
return bmp;
}
So now that you have an image with the gradient in it, all you have to do is to bring over the alpha channel from your original image into the newly created image. We can take the transferOneARGBChannelFromOneBitmapToAnother function from a blog post I once wrote:
public enum ChannelARGB
{
Blue = 0,
Green = 1,
Red = 2,
Alpha = 3
}
public static void transferOneARGBChannelFromOneBitmapToAnother(
Bitmap source,
Bitmap dest,
ChannelARGB sourceChannel,
ChannelARGB destChannel )
{
if ( source.Size!=dest.Size )
throw new ArgumentException();
Rectangle r = new Rectangle( Point.Empty, source.Size );
BitmapData bdSrc = source.LockBits( r, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb );
BitmapData bdDst = dest.LockBits( r, ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb );
unsafe
{
byte* bpSrc = (byte*)bdSrc.Scan0.ToPointer();
byte* bpDst = (byte*)bdDst.Scan0.ToPointer();
bpSrc += (int)sourceChannel;
bpDst += (int)destChannel;
for ( int i = r.Height * r.Width; i > 0; i-- )
{
*bpDst = *bpSrc;
bpSrc += 4;
bpDst += 4;
}
}
source.UnlockBits( bdSrc );
dest.UnlockBits( bdDst );
}
Now you could do something like:
var newImage = GradientImage( original.Width, original.Height, Color.Yellow, Color.Blue, 45 );
transferOneARGBChannelFromOneBitmapToAnother( original, newImage, ChannelARGB.Alpha, ChannelARGB.Alpha );
And there you are. :-)

How to update Texture2D in pixel shader every frame (in D3D10)?

Using D3D10, I am drawing a 2d rectangle and want to fill it with a texture (bitmap) that should change a few times every second (like displaying video).
I am using a shader effect, with a Texture2D variable, and trying to update a ID3D10EffectShaderResourceVariable and redraw the mesh.
My actual usage will be by copying bitmaps from memory, and using UpdateSubresource.
But it did not work, so I reduced it to test switching between two DDS images.
The result is that it draws the first image as expected, but keeps drawing it instead of switching between the two images.
I am new to D3D. Can you explain if this method can work at all, or suggest the right way to do it.
The shader effect:
Texture2D txDiffuse;
SamplerState samLinear
{
Filter = MIN_MAG_MIP_LINEAR;
AddressU = Wrap;
AddressV = Wrap;
};
struct VS_INPUT
{
float4 Pos : POSITION;
float2 Tex : TEXCOORD;
};
struct PS_INPUT
{
float4 Pos : SV_POSITION;
float2 Tex : TEXCOORD0;
};
PS_INPUT VS( VS_INPUT input )
{
PS_INPUT output = (PS_INPUT)0;
output.Pos = input.Pos;
output.Tex = input.Tex;
return output;
}
float4 PS( PS_INPUT input) : SV_Target
{
return txDiffuse.Sample( samLinear, input.Tex );
}
technique10 Render
{
pass P0
{
SetVertexShader( CompileShader( vs_4_0, VS() ) );
SetGeometryShader( NULL );
SetPixelShader( CompileShader( ps_4_0, PS() ) );
}
}
Code (skipped many parts):
ID3D10ShaderResourceView* g_pTextureRV = NULL;
ID3D10EffectShaderResourceVariable* g_pDiffuseVariable = NULL;
D3DX10CreateEffectFromResource(gInstance, MAKEINTRESOURCE(IDR_RCDATA1), NULL, NULL, NULL, "fx_4_0", dwShaderFlags, 0, device, NULL, NULL, &g_pEffect, NULL, NULL);
g_pTechnique = g_pEffect->GetTechniqueByName( "Render" );
g_pDiffuseVariable = g_pEffect->GetVariableByName( "txDiffuse" )->AsShaderResource();
// this part is called on Frame render:
device->CreateRenderTargetView( backBuffer, NULL, &rtView);
device->ClearRenderTargetView( rtView, ClearColor );
if(g_pTextureRV != NULL) {
g_pTextureRV->Release();
g_pTextureRV = NULL;
}
D3DX10CreateShaderResourceViewFromFile(device, pCurrentDDSFilePath, NULL, NULL, &g_pTextureRV, NULL );
g_pDiffuseVariable->SetResource( g_pTextureRV );
D3D10_TECHNIQUE_DESC techDesc;
g_pTechnique->GetDesc( &techDesc );
for( UINT p = 0; p < techDesc.Passes; ++p )
{
g_pTechnique->GetPassByIndex( p )->Apply( 0 );
direct2dDrawingContext->dev->Draw( 6, 0 );
}
// ... present the current back buffer
One solution, not necessarily the best, but one that doesn't use custom shaders, follows (I wrote it in C# / Managed DirectX but it should be easy to transcode.)
Bitmap bmp; //the bitmap that you will use to update the texture
Texture tex; //the texture that DirectX will render
void Render()
{
//render some stuff
bmp = GetNextTextureFrame(); //whatever you do to update your bitmap
Surface s = tex.GetSurfaceLevel(0);
Graphics g = s.GetGraphics();
//IntPtr hdc = g.GetHdc();
//BitBlt(hdc, 0, 0, bmp.Width, bmp.Height, bmpHdc, 0, 0, 0xcc0020);
g.DrawImageUnscaled(bmp, 0, 0);
g.ReleaseHdc(hdc);
s.ReleaseGraphics();
device.SetTexture(0, tex);
//now render your primitives
//render some more stuff
//present
}
The commented out lines are the way I actually did it, using an hBitmap and DC with BitBlt, because it's faster than GDI+. A lot of people will probably tell you that the above is a bad way to do it, because of all the memory locking that has to occur, and they're probably right. But I was able to achieve 30fps with multiple 1920x1080 textures, so regardless of whether it's proper, it works.

Transparent objects covering each other

For an academic project I'm trying to write a code for drawing billboards from scratch; now I'm at the point of making them translucent. I've managed to make them look good against the background but they still may cover each other with their should-be-transparent corners, like in this picture:
I'm not sure what I'm doing wrong. This is the effect file I'm using to draw the billboards. I've omitted the parts related to the vertex shader, which I think is irrelevant right now.
//cut
texture Texture;
texture MaskTexture;
sampler Sampler = sampler_state
{
Texture = (Texture);
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Point;
AddressU = Clamp;
AddressV = Clamp;
};
sampler MaskSampler = sampler_state
{
Texture = (MaskTexture);
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Point;
AddressU = Clamp;
AddressV = Clamp;
};
//cut
struct VertexShaderOutput
{
float4 Position : POSITION0;
float4 Color : COLOR;
float2 TexCoord : TEXCOORD0;
};
//cut
float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0
{
float4 result = tex2D(Sampler, input.TexCoord) * input.Color;
float4 mask = tex2D(MaskSampler, input.TexCoord);
float alpha = mask.r;
result.rgb *= alpha;
result.a = alpha;
return result;
}
technique Technique1
{
pass Pass1
{
VertexShader = compile vs_2_0 VertexShaderFunction();
PixelShader = compile ps_2_0 PixelShaderFunction();
AlphaBlendEnable = true;
SrcBlend = SrcAlpha;
DestBlend = InvSrcAlpha;
}
}
I've got two textures, named Texture and MaskTexture, the latter being in grayscale. The billboards are, most likely, in the same vertex buffer and are drawn with a single call of GraphicsDevice.DrawIndexedPrimitives() from XNA.
I've got a feeling I'm not doing the whole thing right.
You have to draw them in order. From farthest to closest.
I have found a solution. The shaders are fine, the problem turned out to be in the XNA code, so sorry for drawing your attention to the wrong thing.
The solution is to enable a depth stencil buffer (whatever it is) before drawing the billboards:
device.DepthStencilState = DepthStencilState.DepthRead;
It can be disabled afterwards:
device.DepthStencilState = DepthStencilState.Default;

Resources